The invention relates to lock systems, especially but not exclusively to lock systems suitable for securing loads on commercial vehicles.
Thefts of loads from vehicles are a major problem. Typically, commercial vehicles such as vans, lorries or trucks will have cargo bays secured by conventional vehicle lock or padlock and hasp systems, but these are not secure. In particular, since the driver of the vehicle is normally provided with a key to the cargo bay in order to be able to load and unload the vehicle, there is nothing to stop the driver unloading goods improperly at locations other than the authorised destination of the vehicle.
Accordingly, a number of systems to track the movements of vehicles have been proposed. Generally, these systems involve mounting a GPS receiver on the vehicle and monitoring the location of the vehicle on an ongoing basis. For example, U.S. Pat. No. 5,969,595 discloses a system including a GPS receiver mounted on the vehicle. The GPS receiver is used to determine the location of the vehicle when certain conditions occur. If the vehicle is not near a cargo destination when those conditions occur, an alarm signal is transmitted.
The GPS system operates using signals transmitted from a number of GPS satellites orbiting the earth. As will be known, each GPS satellite transmits data that indicates its location and the current time. An atomic clock synchronizes all satellites so that signals are transmitted at precisely the same time. Because of distance variation between satellites and the GPS receiver, data signals will arrive at the GPS receiver at slightly different times. The receiver uses the time difference between the receipt of signals from different satellites to determine the distance of each satellite and hence the location itself.
However, GPS receiving systems are expensive and providing all commercial vehicles in a fleet with GPS systems is often impracticable.
The power requirements of GPS systems are rather high and so in order to get sufficient power to run a GPS receiver continuously small batteries of the type conventionally incorporated in portable units are not suitable. Further, the GPS units need to be connected to a GPS aerial which can see a substantial portion of the sky, and therefore the aerial needs to be mounted on the outside of the vehicle. For security, the GPS unit itself should be mounted in an inconspicuous location within the vehicle. For all these reasons, it is difficult, time-consuming and expensive to install the GPS system in vehicles.
The costs of setting up a monitoring system are not limited to the costs of installing GPS receivers on vehicles. Monitoring equipment needs to be installed and the GPS locations of authorized drop-off points need to be determined. Managing and monitoring such complex systems is not trivial.
There therefore remains a need for a practical security system that is suitable for securing loads on vehicles without incurring excessive costs.
According to the invention there is provided a lock system comprising: a lock unit having a releasable catch for securing an article to be locked, and a memory for storing information about the intended destination of the article; and a key unit having a means for receiving location determining signals; wherein the lock unit and key unit are arranged to register together; the lock system further comprising a means operable to release the catch when the lock unit and the key unit are registered and when the location determined from location determining signals received in the key unit is a destination stored in the memory in the lock unit.
Thus, in the inventions the lock system has a lock unit which has the function of physically securing an article, and a separate key unit which can receive location determination signals. The key unit communicates with the lock unit which only opens when in the correct location.
By providing the power hungry receiver for location determination systems in the key unit and the lock unit can be made smaller and lighter. The lock unit may also have low power requirements since it does not need to communicate with GPS satellites on an ongoing basis.
The lock unit can therefore be smaller and easier to install than the GPS systems previously installed in vehicles.
In embodiments, the lock unit can even be a xe2x80x9cpadlockxe2x80x9d type device which is completely separate from the vehicle, and which can be used to secure special loads without needing to upgrade fleet vehicles.
Even when larger lock units are used, it is still generally possible to provide internal batteries so that there is no need to connect the lock unit to vehicle power lines.
Furthermore, by providing the location determination signal receiver in the key unit there is no need to mount aerials for receiving location determining information on vehicles.
Moreover, by providing a means for receiving location determining information on the key unit it is possible to minimise the costs in setting up the system. The key units can simply be delivered to recipients of goods and can be used to receive location determining information. In embodiments, the key units may have a display for displaying location coordinates. These can be provided to the goods dispatcher for storage in the memory in the lock unit without the need for any special visit to determine the coordinates.
The significant increases in convenience are not at the expense of security. Since the lock unit will only open when the signals received by the key unit relate to a location stored in the memory, goods from a vehicle can only be unloaded in approved locations.
Typically, the location determination signals may be GPS signals though embodiments of the invention may also use other location determining systems, including purely by way of example GLONASS or LORAN. GPS is preferred as GPS equipment is readily available at relatively modest lost.
The invention also relates to the lock unit and to the key unit used in the lock system.
In another aspect, the invention relates to a method of operating a locking system comprising: a lock unit having a catch for securing an article and a memory for storing the location of an intended destination of the article and a key unit having an aerial for receiving location determining information, the method comprising the steps of: bringing the lock unit and the key unit together in close proximity; establishing a communications link between the lock unit and the key unit; receiving location information in the key unit; passing location information to the lock unit through the communications link; and releasing the catch if the location information received in the lock unit matches a location stored in the memory.